Automatic balancing means for unbalanced rotary bodies



June 5, 1951 R. E. CORNWELL 2, 7

AUTOMATIC BALANCING MEANS FOR UNBALANCED ROTARY BODIES Filed June 10, 1948 2 Sheets-Sheet l I as /a "a 7 3s 35 IN VEN TOR.

R41 5w 5. COQNWELL ATTORNEY June 5, 1951 R. E. CORNWELL 2,555,678

AUTOMATIC BALANCING MEANS FOR UNBALANCED ROTARY BODIES Filed June 10, 1948 2 Sheets-Sheet 2 INVENTOR.

BY EAL PH. E. Coewwzu HTTOENEY Patented June 5, 1951 UNITED AUTOMATIC BALANCING MEANS FOR UNBALANCED ROTARY BODIES Ralph E. Gornwell, La Canada, Calif.

Application June 10, 1948, Serial No. 32,058

6 Claims. 1

My invention relates generally to counterbalancing devices, and more particularly to devices of this nature as applied to unbalanced rotary machines.

My invention, in one of its many adaptations, may be associated with vanes or blades as mounted in the rotor of a rotary pump or similar machine, for movement radially to difierent positions relatively to the rotor in response to rotary movement thereof in the stator of the machine, with the attending dynamically unbalanced condition of the rotor setting up vibrations by the action of centrifugal force in variably acting upon the vanes in their respectively different radial positions.

An object of my invention is to provide an automatic balancing means, which is positive and accurate in its operation to neutralize the adverse effect of centrifugal force upon a rotary machine such as the pump above set forth, in such manner that irrespective of the relatively different positions occupied by the vanes radially with respect to the rotor as the latter rotates, theexact amount of counterbalancing force will be applied to the vanes at any one instant to insure that the mass of the rotor and vanes will be in perfect dynamic balance, so as to be smooth running and free of vibration at all operating speeds.

Another object of my invention is to provide an automatic balancing means of the above described character Which is comparatively simple in construction, is compact, positive in action,

and may be operatively associated with the rotor and vane assembly of a rotary machine in a relatively simple manner.

A further object of my invention is to provide a rotary machine having a rotor with radial vanes in Wiping contact at their outer ends with the internal annular surface of the stator to define working chambers in the latter for the pumping of liquid, with the wiping ends of the vanes being formed with grooves whose Walls are of such contour that during rotation of the rotor, any liquid in the working chambers tending to leak past the vanes in opposition to being pumped, will be Whirled rotationally forward with the rotor so as to preclude leakage of the liquid past the vanes.

With these and other objects in view, my invention resides in the combinations, arrangements and functional relationships of elements as set forth in the following specification and particularly pointed in the appended claims.

In the accompanying drawings,

Figure l is a view in side elevation, illustrating one form of my invention applied to a hydraulic pump as one type of rotary machine;

Figure 2 is a transverse sectional view taken on the line 2-2 of Figure 1;

Figure 3 is a sectional view taken on the line 3--3 of Figure 2; and

Figure i is a fragmentary sectional View taken on the line 4-l of Figure 3.

Referring specifically to the drawings, my invention is shown for the purpose of illustration only, associated with a hydraulic pump P of the general character disclosed in my United States Letters Patent No. 2,421,013, issued May 127, 1947. The pump P constitutes one form of rotary machine to which my invention may be applied, and is of the positive displacement type. This pump is composed of a fixed cylindrical casing or stator II! in which is journaled co-axially a cylindrical rotor I I co-acting with the stator to define therebetween an annular working chamber I2 interrupted at one point by a partition I3 mounted in the stator. At opposite sides of the partition I3 there are provided in the stator an inlet I4 and an outlet I5 for the working chamber I 2.,

Slidably mounted in the rotor II in slots Ila thereof for movement radially of the rotor are vanes I6 having rollers I! mounted on stub shafts I la and projecting through slots I'Ib in cover plates Ilc secured by screws lid to close the open sides of the rotor. The rollers I"! work in continuous grooves forming cam tracks I18 in the inner sides of cover plates Illa for the central body portion Iflb of the stator, which plates are secured to the central body portion by tie bolts I00 having nuts ltd, all as shown in Figure 2.

The cam tracks I8 are circular and concentric with respect to the axis of the rotor I I except for a portion I9 opposite the partition I3, which portion is eccentric as shown in broken lines in Figure 1. The concentric portions of the tracks I8 co-act with the rollers I! in maintaining the vanes I6 projected so as to span the working chamber l2 and effect the pumping of liquid therethrough, whereas the portions I9 co-act with the rollers in moving the vanes to a retracted position wherein the vanes clear the partition I3, all during operation of the pump by driving the shaft 25 of the rotor, as more specifically set forth in my Patent No. 2,421,013 above referred to, and forming no part, per se, of my present invention.

In the above described pump structure, the different radial positions occupied by the vanes I6 at any one instant under the action of the cam tracks I8 and rollers I'I, dynamically unbalances the combined masses of the rotor and vanes, with the result that during rotation of the rotor, centrifugal force does not act uniformly on the rotor throughout its circumference, thus intro" ducing vibrational forces which may adversely afiect smooth operation of the rotor at the higher speeds.

In carrying my invention into practice for the purpose of neutralizing the unbalanced mass of the rotor and its vanes 16, I provide for each vane two generally triangular shaped weights 3%. These weights are mounted in the rotor at opposite sides of the respect vanes, for radial movement parallel to the plane of movement of the vanes, by means of guide pins 3| fixed to the rotor and having a working fit in bores 32 in the vanes.

The weights 3@ are operatively connected to the respective vanes for movement inwardly or outwardly, according as the vanes are moved outwardly or inwardly, that is to say, the movements of the weights will be opposite or in the reverse direction to that of the vanes and in such relation thereto as to maintain a uniform distribution of mass around the rotor at the locations of the several vanes irrespective of the positions to which the vanes are moved radially by the cam tracks and rollers H.

The form of operative connection between the vanes and the respective weights which is illustrated, comprises idler pinion gears 35 received in openings 36 in the wallstl of the slots Ma and rotatably mounted on shafts 38 whose ends are supported in the rotor cover plates l'la as shown in Figure 4. The gears 35 constantly mesh with rack teeth 39 formed on opposite sides of the vanes 16, and with rack teeth M formed on the weights 30, so as to provide a positive driving connection between the vanes and weights.

In operation, and with the rotor ll being driven, the vanes IE will be successively moved radially by the eccentric portions IQ of the cam tracks l8 from projected position to retracted position and then back to projected position during each revolution of the rotor. As the gears 35 co-act with the rack teeth 39 and 4!! to reverse the movement of the weights 3!! with respect to that of the vanes, inward movement of the vanes with a corresponding decrease in the centrifugal force acting thereupon, will be compensated for by an outward movement of the respective weights with a corresponding increase in the centrifugal force thereupon. Conversely, outward movement of the vanes with a corresponding increase in the centrifugal force acting thereupon, will be compensated for by an inward movement of the respective weights, with a corresponding decrease in the centrifugal force acting thereupon. Thus, irrespective of the positions of the vanes, the amount of centrifugal force acting upon the rotor at the vanes will be uniform so as to maintain the rotor balanced at all speeds.

As shown in Figures 2 and 3, the outer ends 59 of the vanes I6 which are in wiping contact with the internal annular surface 5| of the stator Ill and with the surface 52 of the partition I3 confronting the periphery of the rotor, are provided with grooves 53 which are generally semi-circular incross section, and whose lengths extend parallel to the rotor axis.

When the rotor II is being driven, the liquid belng pumped through the working chamber l2 tends to leak past the vanes Is in opposition to the pressure in the chamber in advance of ea h vane. The curved contours provided by the walls of the grooves 53 tend to set up a whirling motion upon any liquid which enters the grooves, in a direction to force the liquid rotationally forward with the rotor so as to preclude leakage of the liquid past the vanes.

I claim:

1. In a rotary machine, a stator; a rotor rotatably mounted in the stator and co-acting therewith to provide a working chamber between the periphery of the rotor and the stator; vanes mounted in the rotor at circumferentially spaced locations for movement inwardly and outwardly with respect to said working chamber; means co-acting with said vanes to relatively move them inwardly and outwardly of said working chamber during a predetermined portion of a revolution of the rotor; weights for the respective vanes; means mounting said weights in the rotor in proximity to and in parallelism with the vanes for movement inwardly and outwardly relative to said working chamber; said vanes and weights having gear teeth; and gears co-acting with said teeth to move the weights inwardly or outwardly according as the respective vanes are moved outwardly or inwardly, so as to counteract unbalancing of the rotor by the vanes in relatively different positions at any given instant during rotation of the rotor.

2. In a rotary machine, a stator; a rotor rotatably mounted in the stator and co-acting therewith to provide a working chamber between the periphery of the rotor and the stator; vanes mounted in the rotor at circumferentially spaced locations for movement inwardly and outwardly with respect to said working chamber; means co-acting with said vanes to relatively move them inwardly and outwardly of said working chamber during a predetermined portion of a revolution of the rotor; weights for the respective vanes; means mounting said weights in the rotor in proximity to and in parallelism with the vanes for movement inwardly and outwardly relative to said working chamber; said vanes and weights having rack teeth along confronting sides thereof; and gears rotatably mounted about fixed axes in the rotor in constant mesh with the rack teeth of the respective vanes and weights, so as to move the weights inwardly or outwardl'y according as the vanes are moved outwardly or inwardly, in order to counteract unbalancing of the rotor by the vanes in relatively different positions at any given instant during rotation of the rotor.

3. In a rotary machine, a stator; a rotor rotatably mounted in the stator and co-acting therewith to provide a working chamber between the periphery of the rotor and the stator; said rotor having radial slots at circumferentially spaced intervals; vanes slidably mounted in said slots to occupy projected and retracted positions with respect to said working chamber; means co-acting with said vanes to relatively move them to retracted and projected positions with respect to said working chamber during a predetermined portion of a revolution of the rotor; weights mounted in the rotor at opposite sides of said slots for movement parallel to the lengths of the slots; and positive driving connections between the Weights and the respective vanes, by which projecting movement of the vanes will effect retracting movement of the weights or vice versa, so as to counteract unbalancing of the rotor by the vanes occupying relatively different positions radially in said slots.

with respect to said working chamber; means co-acting with said vanes to relatively move them to retracted and projected positions with respect to said Working chamber during a predetermined portion of a revolution of the rotor; weights mounted in the rotor at opposite sides of said slots for movement parallel to the lengths of the slots; said vanes and weights having gear teeth on their confronting sides; gears; and means rotatably mounting the gears in the rotor between the weights and vanes, with the gears constantly meshing with said teeth so as to project or retract the weights according as the respective vanes are retracted or projected.

5. In a rotary machine, a stator; a rotor having a periphery, a hub, and circumferentially spaced, radially slotted arms joining the periphery and hub; means rotatably mounting the rotor in the stator for co-action therewith in defining a working chamber between the periphery of the rotor and the stator; vanes slidably mounted in said slots to occupy projected and retracted positions with respect to said working chamber; means co-acting with said vanes to relatively move them to retracted and projected positions with respect to said working chamber during a predetermined portion of a revolution of the rotor; guide pins fixed in the rotor at opposite sides of said arms and in parallelism with said slots; Weights slidably mounted on said pins to occupy projected and retracted positions; and means operatively connecting said weights to the respective vanes, to retract or project the weights according as the vanes are projected or retracted.

6. In a rotary machine, a stator; a rotor having a periphery, a hub, and circumferentially spaced, radially slotted arms joining the periphery and hub; means rotatably mounting the rotor in the stator for co-action therewith in defining a working chamber between the periphery of the rotor and the stator; vanes slidably mounted in said slots to occupy projected and retracted positions with respect to said working chamber; means co-actin with said vanes to relatively move them to retracted and projected positions with respect to said working chamber duringa. predetermined portion of a revolution of the rotor; guide pins fixed in the rotor at opposite sides of said arms and in parallelism with said slots; weights slidably mounted on said pins to occupy projected and retracted positions; rack teeth on the confronting sides of said vanes and weights; gears; and means rotatably mounting said gears in said arms, with the gears constantly in mesh with said teeth of the respective weights and vanes, to retract or project the weights according as the vanes are projected or retracted.

RALPH E. CORNWELL.

REFERENCES CITED The following references are of record. in the file of this patent:

UNITED STATES PATENTS Number Name Date 460,522 Bretherton Sept. 29, 1891 810,601 Augustine Jan. 23, 1906 984,061 Augustine Feb. 14, 1911 1,006,896 Augustine Q. Oct. 24, 1911 1,538,075 Wingquist May 19, 1925 2,149,337 Deming Mar. 7, 1939 2,240,465 Serge Apr. 29, 1941 2,421,013 Cornwell May 27, 1947 FOREIGN PATENTS Number Country Date 688,689 Germany Feb. 28, 1940 

